I'm working with a 720p feature length source (117612), and scrubbing is super slow at the moment, to the extent where effective clipping is basically impossible. I thought a solution to this might be to resize the footage, so I tried using a number of different filters (Bilinear, Bicubic and Lanczos), and even at really low resolutions the scrubbing was still at the same speed. I was wondering if there was any way to speed up scrubbing, without exporting it as an avi or mjpeg first.

Also, when I load the footage into VirtualDob (I'm importing using ffvideosource), for some reason the video starts to look like utter shit, even when the original source looks fine. It does stuff like add artifacting and change the colors in a really weird way (Dark grey turning to a lavender type color is the weirdest one so far).

It's slow because of what the decoder has to do to display it... adding more lines to the end of your script is going to make it slower as you are now making it do more work. Temporarily commenting out lines that don't alter the frame rate at all will help with scrubbing (because the script now has to do LESS work).

The only things I could suggest are to clean up your background services (with msconfig) and startup applications (with CCleaner), and other general system maintenance like flushing temp caches and cleaning the registry (both with CCleaner). The latter just being good overall advice; the background and startup stuff is more relevant, as it'd reduce the CPU/memory usage enough that you could get some better performance.

Another general suggestion would be to upgrade to AviSynth+*, in which case you might be able to get a performance boost by using multithreading and/or 64-bit (64-bit doesn't have as many plugins available for it, but if you're not using any except FFMS2 - which has 64-bit builds available - then there's little harm in at least trying it; if using the 64-bit version, you also need to use 64-bit VirtualDub). Not exactly sure how multithreading in AviSynth might interact with VDub, but again, it won't hurt to try.

*the stable release on the official website (r1576) doesn't have multithreading, as it was the last build before MT was introduced; for the MT version (r1689 or higher), see this post on Doom9 (and the one after it) for the notes on how to use it:http://forum.doom9.org/showthread.php?p ... ost1666364

Due to the way the new cache is designed, the MT build should provide lower memory usage even if you use it in single-threaded mode.

Sorry to sound like an idiot, but how do you actually install that build? All that's in the folder is a .dll and two folders. What do you have to do with them? I tried putting them in the avisynth+ folder, but that did nothing, and VirtualDub doesn't recognise SetFilterMTMode.

AviSynth.dll and DevIL.dll (in the system/ folder) replace the ones in C:\WINDOWS\system32 (or sysWOW32 or whatever it is for 32-bit DLLs on 64-bit versions of Windows), and the plugins in the plugins/ folder replace the ones in C:\Program Files\AviSynth+\plugins.